D.I. Duncan McAdam is dispatched home to the Misty Isle. A body has been found buried in a remote location on the Waternish peninsula. Well-preserved in the peat, Isla Matheson—missing for the better part of two decades—is revealed to a shocked island community. A teenage runaway is dead...and no one is talking.

Northern Ireland, spring 1981. Hunger strikes, riots, power cuts, a homophobic serial killer with a penchant for opera, and a young woman’s suicide that may yet turn out to be murder: on the surface, the events are unconnected, but then things—and people—aren’t always what they seem. Detective Sergeant Duffy is the man tasked with trying to get to the bottom of it all. It’s no easy job—especially when it turns out that one of the victims was involved in the IRA but was last seen discussing business with someone from the loyalist Ulster Volunteer Force.

Five years ago, DCI John Lomond led the search for notorious Glasgow child-killer ‘The Sandman', until personal tragedy forced him off the case. In Lomond's absence, the killer was never found. Now, with nothing but work left in his life, Lomond remains obsessed with the case–despite the nightmares it brings. When a child is abducted in similar Sandman fashion from an affluent Glasgow suburb, Lomond is brought in to find them before it's too late.

In a peaceful retirement village, four unlikely friends meet weekly in the Jigsaw Room to discuss unsolved crimes; together, they call themselves the Thursday Murder Club. When a local developer is found dead with a mysterious photograph left next to the body, the Thursday Murder Club suddenly find themselves in the middle of their first live case.

Two years ago, a hostile Prime Minister launched the Monochrome inquiry, investigating "historical over-reaching" by the British Secret Service “to investigate historical over-reaching.” Monochrome’s mission was to ferret out any hint of misconduct by any MI5 officer—and allowed Griselda Fleet and Malcolm Kyle, the two civil servants seconded to the project, unfettered access to any and all confidential information in the Service archives in order to do so. But MI5’s formidable First Desk did not become Britain’s top spy by accident, and she has successfully thwarted the inquiry at every turn.